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Thread: Speaking Of Gas Tanks, Very Clean is Not Completely Clean

  1. #51
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    Re: Speaking Of Gas Tanks, Very Clean is Not Completely Clean

    So what happened to the weldor? He had to of messed his shorts. Hopefully no injuries.

    My big question is; what is going to happen with that fancy tank? Looks mighty expensive. What did it go into and is that a military paint job?
    Last edited by Insaneride; 07-07-2015 at 08:41 PM.

  2. #52
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    Re: Speaking Of Gas Tanks, Very Clean is Not Completely Clean

    Quote Originally Posted by Insaneride View Post
    So what happened to the weldor? He had to of messed his shorts. Hopefully no injuries.

    My big question is; what is going to happen with that fancy tank? Looks mighty expensive. What did it go into and is that a military paint job?
    The welder suspected it, so he had the guy who cleaned it stand close. The welder does not get too shaken up.

    It is a boat tank.

    The welder felt bad for the guys trying to get the boat in the water, after a couple years of working on it, so he made him a brand new one in a couple hours. They were laughing about it actually. You can see in their faces when they were telling what happened they must have had a moment where they thought that was it.

    Sincerely,

    William McCormick
    If I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.

  3. #53
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    Re: Speaking Of Gas Tanks, Very Clean is Not Completely Clean

    I'm kind of a 'tank killer' in this manner, and I'd say most points of view here are valid and reliable for anyone considering working on used tanks.

    I've done it a lot. But now my experience is separated into the Before and After. In 1979 (might have been 1980?) I was bullet proof as many young welders are, and I could weld anything! I could weld the 'crack of dawn', I could weld a "broken heart", I could weld any gap "you could jump a 4year old stallion over at a full gallop".

    I was the most informed welder in a 1,000 miles and some used gasoline tank was no big deal? Why not? Drain 'em, rinse 'em and run some argon in (never mind any calculations) and weld it up, get it out the door.

    That was Before.



    This is After.

    I was resting fully over the missing top of this tank that was washed and cleaned and purged. I hope this picture might help those who might possibly still be in their 'bullet proof' stages of life to consider what might happen if you weld on tanks that have had fuel in them?

    Some will weld used tanks, I still do, but my cleaning costs often approach a new build because of the steam cleaner time and the multiple rinses and the bottle of purge gas and I do use an LEL + O2 meter along with the rest.

    It can be done, but as Ronald Reagan said "Trust, but Verify" its the only life you get.

    Cheers,
    Kevin Morin

  4. #54
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    Re: Speaking Of Gas Tanks, Very Clean is Not Completely Clean

    Quote Originally Posted by Kevin Morin View Post
    I'm kind of a 'tank killer' in this manner, and I'd say most points of view here are valid and reliable for anyone considering working on used tanks.

    I've done it a lot. But now my experience is separated into the Before and After. In 1979 (might have been 1980?) I was bullet proof as many young welders are, and I could weld anything! I could weld the 'crack of dawn', I could weld a "broken heart", I could weld any gap "you could jump a 4year old stallion over at a full gallop".

    I was the most informed welder in a 1,000 miles and some used gasoline tank was no big deal? Why not? Drain 'em, rinse 'em and run some argon in (never mind any calculations) and weld it up, get it out the door.

    That was Before.



    This is After.

    I was resting fully over the missing top of this tank that was washed and cleaned and purged. I hope this picture might help those who might possibly still be in their 'bullet proof' stages of life to consider what might happen if you weld on tanks that have had fuel in them?

    Some will weld used tanks, I still do, but my cleaning costs often approach a new build because of the steam cleaner time and the multiple rinses and the bottle of purge gas and I do use an LEL + O2 meter along with the rest.

    It can be done, but as Ronald Reagan said "Trust, but Verify" its the only life you get.

    Cheers,
    Kevin Morin
    Glad you made it. Good observations.

    You know we are all talking about old fuel tanks, residue, one drop of aromatic hydrocarbon. What about the tank itself? It is a bomb shell. Without that component there could be no bomb from the substances that strike fear into our hearts.

    My point is that a little cutting oil, or a small bit of wax, the wax could be from packaging, wax impregnated paper, if it gets into the tank, you have the same scenario waiting for you. We are really battling the tank not the fuels. So if you are not sure the tank is clean no matter what was or wasn't in there do not weld it.

    Also when welding a wet tank, or a tank with water in it. You can also create an amazing steam bomb. So it is the tank not the substance so much.

    I personally TIG welded a fillet weld on steel plates, that were sealing off an 8"x 8" piece of steel box tubing. I still had ten inches to go on the final weld. I had cooled the thing down with water in between welding the two plates, because it was summer and the heat coming from it was truly unreal. The shop had to be about 100 degrees or more. It was welding really well and fast, when I hit a drop of water, that may have dripped down from the outside or the inside and made it into the joint I was welding. The pressure created moved me and the box tubing. The electrical sound the pressure and heat was something you would have to see for yourself. So there is no safe way to deal with a tank and contaminants.

    You do have to watch purge gases in a confined space. They are extreme insulators, dielectrics. Most people look at a light switch and say the air between the gap in the light switch contacts or points, stops the electric from flowing. And although we use air to do that. You would be mistaken to believe that the air stops electricity. Air, glass, and mica are the fastest conductors of electricity voltage, and the worst conductors of amperage. Silver, copper and aluminum are the slowest conductors of electricity voltage and the best conductors of amperage. That is why when you open a light switches contact, the immediate communication of voltage across the air gap, causes the air, to ramp in voltage from one point to the other. So fast that on one contact there is so much voltage that it stops the flow of voltage from the power source. It is as if you were charging a battery and you completely charged it, the battery charger can send no more amperage, because there is an almost equal voltage in the battery repelling the power source flow. The light switch contacts are an amazingly small capacitor or battery that charge and discharge in a tiny fraction of a second. The only way to stop electricity, is with a certain amount of electricity.

    The light switch and its air gap does not actually stop all the electricity, it does stop most of it. My point is that when you purge with argon, it is such a fast communicator of electricity, and does conduct more current then regular air, many times more before it breaks down as air does. That with liquid in the tank it could create a problem. Or even other gases in the tank that may not be able to withstand the electrical charge created between the dielectric Argon gas, and the top wall of the tank, may actually turn white and expand all the gases violently. I do not see this as happening often however under the right situation it could happen. From the limited experiments I did.



    Sincerely,

    William McCormick
    If I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.

  5. #55
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    Re: Speaking Of Gas Tanks, Very Clean is Not Completely Clean

    As welders we learn that metals have porosity. They have a great affinity for absorbing hydrocarbons. This is most easily seen when welding an old aluminum part that has been exposed to hot oil. Think Harley crankcase, cylinder heads, transmission cases. I've cleaned those as well as I could only to see the oil pour out of them once the heat hits them. In like manner, Diesel or gasoline can be absorbed or form pockets inside of closed spaces such as fuel tanks.

    The thing that bothers me about fuel tanks is that even with expensive equipment for cleaning, you are never really sure if they are clean enough. There's always that wonder in the back of your mind. That doesn't mean that they can't be welded, it's just that you really have to be careful and your customers need to understand why this sort of work costs more.
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  6. #56
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    Re: Speaking Of Gas Tanks, Very Clean is Not Completely Clean

    Quote Originally Posted by gnm109 View Post
    As welders we learn that metals have porosity. They have a great affinity for absorbing hydrocarbons. This is most easily seen when welding an old aluminum part that has been exposed to hot oil. Think Harley crankcase, cylinder heads, transmission cases. I've cleaned those as well as I could only to see the oil pour out of them once the heat hits them. In like manner, Diesel or gasoline can be absorbed or form pockets inside of closed spaces such as fuel tanks.

    The thing that bothers me about fuel tanks is that even with expensive equipment for cleaning, you are never really sure if they are clean enough. There's always that wonder in the back of your mind. That doesn't mean that they can't be welded, it's just that you really have to be careful and your customers need to understand why this sort of work costs more.
    A friend of mine years ago had a race shop. The man truly bought and or built expensive equipment to do the right job. Well he bought one of those special hot wash systems all automated. So the guys would not go blind dipping parts in a hot tank. You put your parts in the machine and it did a hot sodium hydroxide wash of the parts. I welded some stuff that went through that system and it was amazing. Really no oil whatsoever. Very dry surface deep down.

    But the rinse water that went in the cesspool would eventually detonate the cesspool, they called it Old Faithful. When it would detonate it would blow all the water out of the toilet. I was there one day when it went off. And I said "what the hell was that?" and they told me the story. The ceiling of the bathroom would actually drip for minute or so after it happened. I was laughing and clowning and when I got to the question has anyone ever been on it when it went off. No one was laughing anymore. Not even me.


    Sincerely,

    William McCormick
    Last edited by William McCormick; 07-09-2015 at 12:10 AM.
    If I wasn't so.....crazy, I wouldn't try to act normal, and you would be afraid.

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